Use of softening additives in polyurethane foam

ABSTRACT

An amine softening additive is useful in softening all-water blown flexible polyurethane foam to achieve low IFD valves while retaining the other commercially necessary properties of the foam. The additives are tertiary amine polyisocyanate catalysts which contain at least one contiguous three carbon chain and should be added to the foam system at about 0.1 to 2.0 parts per hundred of polyol.

This application .Iadd.is a Reissue of U.S. patent application Ser. No.08/326,293, filed Oct. 20, 1994, now U.S. Pat. No. 5,539,011, which.Iaddend.is a continuation-in-part of U.S. patent application Ser. No.08/101,189 filed on Aug. 3, 1993, now abandoned.

BACKGROUND OF THE INVENTION

Environmental pressures and ever-tightening governmental regulationshave shifted the flexible slabstock polyurethane foam market away fromthe use of conventional blowing agents and auxiliary blowing agents(ABA's) such as CFC-11, methylene chloride, 1,1,1-trichloroethane, andmethyl chloroform. Generally, this pressure has forced the polyurethanefoam industry towards higher-water based formulations. The physicalblowing of such high-water polyurethane foam formulations occurs fromthe carbon dioxide given off as a result or the reaction of water andisocyanate. This blowing replaces the traditional foam expansion derivedfrom the volatilization of conventional blowing agents.

The shift to these higher-water formulations and away from conventionalblowing agents has placed many additional demands on flexible slabstockfoam production. First, the use of higher amounts of water typicallyresults in increased foam exotherms leading to increased foamdiscoloration, scorching problems and potential for fire. Second, anincreased urea content is common in higher water systems leading tohigher hardness values. Thus, some softer foam grades are not readilyattainable using only water as the sole blowing agent. Third, a dramaticdecrease in foam quality as evidenced by key physical properties of thefoam such as compression sets, tensile strengths, tear strengths, andelongation values are also common in most conventional higher watersystems. These higher water systems also typically are more difficult toprocess than their conventional lower water counterparts.

These and related problems have generated several solutions to overcomethe inherent pitfalls of current all-water-blown slabstock foamproduction technology. One of the primary chemical solutions to haveevolved to date is the use of low index formulation technologies, suchas described in U.S. Pat. No. 4,950,694 to Hager, which allow for lowerexotherms and lower load (hardness or indentation force deflection IFD!)values relative to conventional index, all-water-based systems. Withsuch low index systems, many high quality, lower load foam grades can beproduced without the environmentally harmful conventional and auxiliaryblowing agents. However, it is desirable to achieve lower IFD ABA-freefoams than can be achieved with these low index technologies, whichtypically are limited commercially to a minimum 25% IFD value (that is,the load at 25% compression of the foam in lbs. per 50 square inches) ofabout 19-22 lb. in lower density foam (<1.5 lbs./f³) and greater thanabout 22 lb. in higher density (>1.5 lbs./f³) foam, measured accordingto ASTM-3574.

On another note, the use of amine based isocyanate dimerization ortrimerization catalysts has been known for use in manufacturing rigidpolyurethane foams. These catalysts lead to isocyanurate linkages whichare highly crosslinked and generate brittle, rigid foam structures.Thus, these catalysts have been used in rigid foams wherein, unlikeflexible foam, high degrees of cross-linking are desirable. Inparticular, U.S. Pat. No. 3,804,782 teaches the general use of1,3,5-tris-(3-dimethylaminopropyl)-1,3,5-triazine (CAS 15875-13-5) inrigid polyurethane foams. Many rigid foam systems have also includedN,N-Dimethyl cyclohexylamine (CAS 98-94-2) as an early stage co-catalystin catalyst blends intended to produce trimerized isocyanate structuresin foams (WO9216574).

Additionally, U.S. Pat. No. 4,101,466 discloses the general use ofbis-(3-dimethylaminopropyl) methlylamine (CAS 3855-32-1) in polyurethanefoams and U.S. Pat. No. 5,173,516 teaches the use ofbis-(3-dimethylaminopropyl) methylamine as a processing aid for highresiliency (HR) foam systems. The catalyst N,N-dimethylpiperazine (CAS106-58-1) (DMP) has been used primarily as a processing aid in polyesterfoams, though one patent citation (U.S. Pat. No. 3,66 1,808) claims theuse of N,N-dimethylpiperazine in a catalyst blend for the purpose orreducing the volatility of the catalyst mixture. Such processing isdifferent from the physical enhancement of foam, e.g., an increase foamsoftness, because while it may increase the cure rate of the foam, thecatalysts have not been known to soften the HR and polyester foams.

Moreover, German Patent No. 4030515 discloses the use of3-(dimethylamino)-1-propylamine (DMAPA) (CAS 109-55-7) to preparecatalysis useful in rigid polycther polyol foams. This catalyst has alsobeen used to catalyze HR foams according to the teachings of DE2116535.

SUMMARY OF THE INVENTION

The present invention describes a new additive to be used in concertwith all-water blown low index flexible polyurethane technology as ameans of dramatically softening the resultant foams. These additivebased foams yield similar or better physical properties than the higherIFD (harder) foams without the additive.

Specifically, this invention relates to the use of certain tertiaryamine catalysts to reduce the IFD values (hardness properties) offlexible polyurethane slabstock foam prepared using conventionalsecondary hydroxyl polyether polyols. More particularly, this inventionrelates to these amine softening additives used in all-water-based foamformulations, particularly those or low isocyanate index (<100). Thesefoams exhibit a substantially open cell structure without crushing andwithout the use or any ABA's such as chlorofluorocarbons, methylenechloride, or other halocarbons.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is based on the unexpected findings that smallamounts or certain amine foam additives dramatically soften low densityall-water based flexible polyurethane foams while maintaining the otherdesirable properties of the foam, e.g., small cell size, acceptablecompression, etc. and without significantly affecting processability.Polyurethane foam formulations contemplated herein are typicallyall-water-blown low index formulations using stabilizing additives suchas those discussed in U.S. Pat. No. 4,950,694 to Hager, which isincorporated herein by reference.

The amine additives for use herein are typically not used inconventional flexible slabstock foams. Most conventional secondaryhydroxyl polyol based flexible slabstock foam amine catalyst packagesrely heavily on blends of strong blowing and gelling catalysts such asbis(dimethylaminoethyl) ether and triethylenediamine (TEDA). Thecatalysts of this invention are relatively weak polyurethane catalystsin comparison and typically are used in rigid, molded, and/or highresiliency (HR) foams. Such catalysts have been used in rigid foamssystems to promote isocyanate dimerization, trimerization, and (cyclo)trimerization as one method to help harden the foam systems or as HRmolded or polyester based foam processing aids as means to control earlystage foam exotherms and foam gelation as it relates to flow. Thus, thatthese catalysts producing a large softening affect in conventionalflexible polyurethane foams, foams which typically require much strongercatalysts, is unexpected.

The amine additives of this invention yield foam with equal or superiorprocessing and physical properties to all-water based polyurethane foamswhile exhibiting very large IFD reductions of the foams incorporatingthem. These properties have been mostly observed with low density, softfoam (about 1 pcf pound per cubic foot!) grades. High quality foams withIFD reductions of up to about 9 lb. as compared to foams without theamine additive have been seen in these 1 pcf foams upon the addition ofsmall quantities of the amine additives of the present invention.Similar additions or small quantities of these amine additives to highdensity (about 1.8 pcf), soft foam grade, all-water based formulationshave shown IFD reductions approaching about 2.5 lbs. Thus, the additivesmay be described by their affect of producing a useful flexible foamwith a 25% IFD of 5 to 18 lbs., preferably 10 to 18 lbs. in lowerdensity (<1.5 pcf) foam and 10 to 21 lbs., preferably 16 to 21 lbs. inhigher density (>1.5 pcf) foam. Moreover, 90% compression sets (measuredaccording to ASTM 3574) of less than about 15% can be achieved with thepresent invention. Such magnitudes of IFD change with minor amounts ofamine additives are surprising, especially given that some or theseadditives are used to harden rigid foam or are used mainly as processingaids.

Cell Size is another important property in foam. A fine or small-sizedcell structure is generally accepted as leading to a silky feel or handof a given piece of foam. Additionally, the relative degree ofregularity of the cell sizes also strongly contributes to foam physicalproperties such as tingemailing and compression sets in many foamgrades. Highly desirable maximum cell sizes of less than about 2.0 mmare achieved in the present by disclosed foam formulation.

Airflow data provides a numerical measure of the amount of air to flowthrough a standard size piece of foam at a standard air pressure andtemperature. This gives a measure to the relative openness or closednessof a given piece of foam. Foams with higher airflows are more open andconversely those with lower airflows are considered closed or tighter.Airflows achieved in foams of the present invention are greater thanabout 80 cfm/ft² for 1.0 pcf foams and greater than about 30 cfm/ft² forhigher density foam. Thus, the airflows of the presently disclosed foamsare relatively high and indicate good quality open-celled foam. Theseairflow ranges are for non-FR (flame retardant) foam grades. FR foamswould be, by definition, of lower airflows.

Blow times are an important property of foam disclosed herein due to themechanical processing limitations associated with the standard foamproduction equipment used in the industry. Since most commercialslabstock foam is produced on continuous equipment, it is desirable tohave foam formulation blowoff times within pre-described ranges that areoptimal for a given machine. Outside of the normal blowoff time windows(i.e., 75-180 sec. on most equipment), the production or useful foam ina continuous, consistent manner is problematic as throughputs, fallplatesettings and catalyst levels, become extremely difficult to optimize,thus inhibiting the production these foam systems. Blow times of most ofthe presently disclosed foam formulations are in the range of about75-180 seconds and most preferably around 100-140 seconds and thus, fallwithin the commercially necessary parameters. A few of the disclosedformulations are slightly below this 75 second limit and yet arebelieved to be close enough to said limit that further optimizations ofall of the formulation components should bring these into the range ofcommercially producable foam.

Although the mechanism of this softening by the amine additives isuncertain, it is believed to be catalytic in nature and to possibly be afunction of the total formulation water as the higher density foams(less water) show a lesser degree of softening than do the lower densityfoams (with higher water levels).

Components of the Flexible Polyurethane Slabstock Foam

The flexible polyurethane slabstock foam contemplated herein iscomprised of (I) one or more polyols; (II) one or more organicisocyanates; (III) blowing agents; (IV) one or more surface activeagents; (V) one or more catalysts; (VI) one or more foam processingaids; (VII) amines softening additives; and (VIII) optionally, one ormore of (VIII) other standard ingredients known to those skilled in theart. To follow is a description of each component of the invention.

Polyol

The polyols, Group (I), which can be utilized in the present inventioninclude, but are not limited to, the following polyether polyols: (a)alkylene oxide adducts of polyhydroxyalkanes; (b) alkylene oxide adductsof non-reducing sugars and sugar derivatives; (c) alkylene oxide adductsof polyphenols; and (d) alkylene oxide adducts or polyamines andpolyhydroxyamines. Alkylene oxides having two to four carbon atomsgenerally are employed, with propylene oxide, ethylene oxide andmixtures thereof being particularly preferred.

Any material having active hydrogens, as determined by the Zerewitinoffmethod, may be utilized to some extent and therefore is included withinthe broad definition of the polyols of Group (I). For example,amine-terminated polyether polyols, hydroxyl-terminated polybutadienepolyols and many others are known and may be used as a minor componentin combination with the above-identified conventional polyether polyols.

Generally, the polyol compound (I) should have an equivalent weight inthe range of about 400 to about 1500 grams/equivalent and an ethyleneoxide content of less than 20%. Preferably the equivalent weight is inthe range of about 500 to about 1300 grams/equivalent and mostpreferably between about 750 and 1250 grams/equivalent. The polyol orpolyol blend should have an average hydroxy functionality of at least 2.The equivalent weight is determined from the measured hydroxyl number.The hydroxyl number is defined as the number of milligrams of potassiumhydroxide required for the complete hydrolysis of the fully acetylatedderivative prepared from one gram of polyol. The relationship betweenthe hydroxyl number and equivalent weight is defined by the equation: OH=56,100/equivalent weight, where OH equals the hydroxyl number of thepolyol. Thus, polyols have hydroxyl numbers preferably in the range ofabout 43 to about 110, and more preferably in the range of about 45 toabout 75.

Preferably the polyols should include the poly(oxypropylene) andpoly(oxyethylene-oxypropylene) triols. Ethylene oxide, when used can beincorporated in any fashion along the polymer chain. Stated another waysthe ethylene oxide can be incorporated either in internal blocks, asterminal blocks, or may be randomly distributed along the polyol chain.However, the manner of incorporation and the ethylene oxide content ofthe polyol preferably is as noted above. Thus, ethylene oxide is used ata level below about 20% by weight, preferably below about 15% by weight,and is located primarily within the interior of the polyol chain. Thus,preferably the polyols are substantially secondary hydroxyls.

Preferably, a portion or all of the polyol component may be added in theform of a polyol polymer in which reactive monomers have beenpolymerized within a polyol to form a stable dispersion of the polymersolids within the polyol.

The amount of polyol used is determined by the amount of product to beproduced. Such amounts may be readily determined by one skilled in theart.

Isocyanates

Organic isocyanates (Group II) useful in producing polyurethane foam inaccordance with this invention are organic compounds that contain, onaverage, between about one and a half and about six isocyanate groups,and preferably about two isocyanate groups. Suitable organicpolyisocyanates include the hydrocarbon diisocyanates, e.g., thealkylene diisocyanates and the aryl diisocyanates and more specifically,diphenylmethane diisocyanate and toluene diisocyanate ("TDI"). Preferredpolyisocyanates are 2, 4 and 2, 6 toluene diisocyanates and theirmixtures having a functionality of about 2, which are broadly referredto herein simply as TDI. The most preferred polyisocyanate is 80/20 TDI(i.e., a mixture of 80% 2,4-toluene diisocyanate and 20% 2,6-toluenediisocyanate).

The amount of isocyanate to be used is dependent upon the index of foamdesired and the final properties of the foam to be formed. As statedabove, if the index is 100, then there is a stoichiometric equivalent ofthe amount of isocyanate needed to react with the polyol component(Group I) and the other active hydrogen containing components in thesystem. While the present invention may be practiced in a wide range ofindexes, 60-120; however, the preferred range of use is indexes between80 and 115; and most preferably the range of indexes is 85-95.

Blowing Agents

Water (Component III) is preferably the sole blowing agent to producecarbon dioxide by reaction with isocyanate. Water should be used atabout 1 to 12 pphp (parts per hundred of polyol (Group I)) andpreferably between 2 and 10 pphp. At foam indexes below 100, thestoichiometric excess of water cools and blows via vaporization, not aspart of the reaction to produce carbon dioxide. Other blowing agentsthat are conventionally used in the art may be used herein, but becauseof the utility of the formulation large amounts of such agents are nolonger needed and in many cases none are needed at all.

Surface Active Agents

Suitable surface active agents (Group IV) (also known as surfactants)for slabstock applications include "hydrolyzable"polysiloxane-polyoxyalkylene block copolymers. Another useful class offoam surface active agents are the "non-hydrolyzable"polysiloxane-polyoxyalkylene block copolymers. The latter class ofcopolymers differs from the above-mentioned polysiloxane-polyoxyalkyleneblock copolymers in that the polysiloxane moiety is bonded to thepolyoxyalkylene moiety through direct carbon-to-silicon bonds, ratherthan through carbon-to-oxygen-to-silicon bonds. Most preferred are thesilicone surfactants L-640, L-620 and L-603 commercially available fromOSi Specialties, Inc. of Danbury, Conn. The surface active agent shouldbe present at about 0.0001 percent to about 7-8 percent by weight of thetotal reaction mixture.

Catalysts

component (v) is a combination of standard tertiary amine andorganometallic polyurethane catalysts which should be present at about0.0001 to 5 weight percent of the reaction mixture. Suitable catalystsinclude, but are not limited to, dialkyltin salts of carboxylic acid,tin salts of organic acids, triethylene diamine (TEDA), bis(2,2'-dimethylaminoethyl) ether and similar compounds that are wellknown to the art.

Foam Processing Aid

A foam processing aid (Group VI) is used for enhancing the properties oflow density, flexible slabstock foam, said foam processing aid includesa crosslinking agent and/or extending agent and preferably a sufficientamount of a cell opening agent, to yield a polyurethane foam having aporosity greater than about 40 cubic feet per minute per square foot(CFM-ft²), although this is dependent on foam grade.

A relatively low molecular weight (generally below about 250 gms/mole)polyfunctional glycol crosslinking/extending agent is preferred to makestable, free-rise foams. The equivalent weights of these agents aregenerally less than about 200, but in certain circumstances they may behigher. The reactive group functionality of these compounds should be atleast two, and preferably in a mixture of agents, at least one has afunctionality or three or greater. Polyfunctional isocyanate reactivecompounds, such as a hexahydroxy functional alkane of a molecular weightor approximately 182 gms/mole with an equivalent weight of 30, arepreferred. The number of such functionalities may be greater than thelimitation of eight. The polyols that are or use herein, unlike thosepreviously described, may include primary polyols.

The crosslinking/extending agent should be present between about 0.1 and10 pphp and preferably, between 0.2 and 5 pphp.

Other polyfunctional isocyanate reactive components may be used with thepresent invention. These include, other high molecular weightcross-linking agents that are polyvinyl alcohol homo- and copolymers ofnumerous monomers, including polyvinyl butyral, which has a molecularweight of 2,000-20,000, hydroxyethyl(meth)acrylate homo- and co-polymersof molecular weight 2,000-20,000, hydroxyl derivatives or polyvinylethers such as hydroxybutyl vinyl ether homo- and co-polymers ofmolecular weight 2,000-20,000 and similar polymers. These polymers mayhave equivalent weights greater than 200 which may be preferred incertain usages. Generally, the equivalent weight is between 50 and than2,000. Moreover, the molecular weight of these polymers are from 2,000to 20,000.

The cell opening agent, is preferably a polyethylene oxide monol orpolyol of an equivalent weight greater than 200, with 200-1,000 beingpreferable, with a hydroxyl functionality of two or greater. Forexample, one of the preferred cell opening agents is a polyethyleneoxide adduct of glycerol of a molecular weight or about 990 gms/mole,with an equivalent weight of about 330. The cell opening agent should bepresent at about 0.001 to 20 pphp. Note that in certain cases despitethe equivalent weight difference, the cell opener may act as acrosslinking agent and vice-versa, thereby reducing the need for thecrosslinking agent or cell opening agent, as the case may be.

The weight ratio of the cell opening agent to crosslinking agent presentin the composition is critical and should be about 10:1 to 1:2, with 6:1to 3:1 being preferable. Combinations of cell opening agent andcrosslinking agent within this preferred range have a symbiotic effecton the foam. For example, when a cross-linking agent was used alone,foams were stable with no splits, but were tight with low air flowresulting in poor compression sets. If a cell opening agent is usedalone the foam will be very open with center splits and possessedmoderate compression sets at best. In the preferred range of ratios,combinations lead to spilt-free, stable open foams with low compressionsets.

It has been observed that certain of the amine softening additivesbehave quite differently in the presence of different cell openers,crosslinking/extending agents, or differing ratios of the two. The IFDproperty of foam is very dependent on these components and ratios.Changing the cell openers, crosslinking/extending agents, the ratio ofthese two components, and/or the amine softening additives will resultin vastly different foam performance and/or property characteristics.This will require optimization of the foam formulation toward thedesired physical properties of the resultant foams using these componentmixtures. Such optimizations of other foam components will be clear toone skilled in the art. For example, when using the 990 gm/mole cellopener versus the 550 gms/mole cell opener, additional tin and/or aminemay be required for the production of foam of similar processability.

Amine Additives

The specific softening amine additives (VII) of this invention aretertiary amino polyisocyanate catalysts which contain at least onecontiguous three (3) carbon chain, which is not interrupted by anon-carbon atom. Said polyisocyanate catalysts may be polyisocyanuratecatalysts which cause crosslinking amongst the isocyanate groups. Thesecatalysts also include some polyester foam and HR foam processing aids.These types of catalysts are well known in the art and the type ofstructures included therein have been known in the art. See, e.g..Malwitz, N. et. al., "Amine Catalysis of Polyurethane Foams," 30thAnnual Polyurethane Technical/Marketing Conference, 338, 345 (1986),which is incorporated herein. The primary prior use of said catalystshas been to harden rigid polyurethane foam. Moreover, these catalystshave been used to aid rigid HR and polyester foams with processing.

Exemplary for use herein are 1,3,5-tris-(3-dimethylaminopropyl)-1,3,5-triazine (commercially available from OSi Specialties, Inc. ofDanbury, Conn. under the trade name NIAX® C-41) andbis-(3-dimethylaminopropyl) methylamine (commercially available from AirProducts of Allentown, Pa. under the trade name POLYCAT® 77). Otherexamples for use herein include 1, 4, Dimethylpiperazine (DMP) anddimethyl cyclohexyl amine (NIAX® C-8 available from OSi Specialties,Inc.). The choice of the particular additive depends upon the cellopener and crosslinking agent used in the composition.

These amine softening additives or additive blends are used inrelatively small amounts 0.1 to about 2 pphp, in addition to normal tinand amine catalyst.

Other Additives

Solid stabilizing polymers (VIII) and other additives, including flameretardants, colorants, dyes and anti-static agents, which areconventionally known in the art may be used with the formulations of thepresent invention. Those additives listed in U.S. Pat. No. 4,950,694 areexemplary and are incorporated herein. Of particular note are additivessuch as JEFFAMINE® amine terminated polyols (available from Texaco ofHouston, Tex.) and more specifically, ethylene oxide, propylene oxidebased block copolymers which are terminated with a primary amine.

Process

Initially, the required amount of toluene di-isocyanate (TDI) iscalculated from the amount of polyol, water, foam processing aid and thedesired index. The polyol, surface active agent, amine catalyst, amineadditive, water, foam processing aids, and other additives are mixedtogether and agitated. During such agitation, the organometalliccatalyst and the isocyanate are added and mixing continues untilhomogeneous. When the mixing stops, the liquid foam mass is poured asquickly as possible into the desired form for the foam. Frequently, thisis accomplished in a continuous process. After gas release startsoccurring, the foam may be mechanically cooled.

EXAMPLES

The following examples which indicate the utility of the presentinvention, but are not intended to limit the scope thereof, use thefollowing designations, terms, and abbreviations:

Polyol designates a 56 hydroxyl number polyalkylene triol (nominal)produced by reacting propylene oxide (90%) and ethylene oxide (10%) ontoglycerin. This material has predominantly secondary terminal hydroxylgroups.

Water indicates distilled water.

TDI designates commercially available 80/20 mix of toluene diisocyanateisomers.

Tin designates a standard commercial organotin catalyst. T-9, consistingmainly of stannous octoate.

Amine designates a balanced blow and gel catalyst, typically NIAX®catalyst C-183 (available from OSi Specialties, Inc.).

Silicone designates a standard commercial non-hydrolyzable surfactant(polyether-silicone copolymer) used for conventional slabstock foam,Silicone L-620, available from OSi Specialties, Inc.

Modifier 1 designates Geolite® modifier GM-201 foam processing aid whichcontains 25% of water (commercially available from OSi Specialties,Inc.)

Modifier 2 designates Geolite® modifier GM-205 which contains foamprocessing aid which contains 28% water. (Commercially available fromOSi Specialties, Inc.)

Modifier 3 comprises about 25% by weight, of water, about 64%polyethylene oxide adduct of glycerol of a molecular weight of about 990gms/mole, with an equivalent weight of about 330, and about 11%hexahydroxy functional alkane of a molecular weight of about 182gms/mole with an equivalent weight of about 30.

Additive A designates ORTEGOL® 310 softening agent. (Available from Th.Goldschmidt of Hopewell, Va.)

Additive B is Carapor 2001 softening agent. (Available from Shell ofHouston, Tex.)

Additive C is NIAX® C-41 catalyst. (Available from OSi Specialties,Inc.)

Additive D is POLYCAT® 77 catalyst. (Available from Air Products.)

Additive E is NIAX® C-8 catalyst. (Available from OSi Specialties, Inc.)

Additive F is JEFFAMINE® ED-600 polyol. (Available from Texaco.)

Additive G is 1,4-dimethylpiperazine. (Available from Aldrich ofMilwaukee, Wis.)

Additive H is dirnethylaminopropylamine. (Available from Aldrich.)

Additive I is NIAX® catalyst A-1. (Available from OSi Specialties, Inc.)

Additive J is NIAX® catalyst A-33. (Available from OSi Specialties,Inc.)

Additive K is 3-Dimethylamino-N,N-dimethylpropionamide. (Available fromAldrich)

Additive L is ARMEEN® DM-16D catalyst. (Available from Akzo of Chicago.Ill.)

Additive M is NIAX® C-5 catalyst. (Available from OSi Specialties, Inc.)

Additive N is tetramethyl-1,3-butanediamine. (Available from OSiSpecialties, Inc.)

Additive O is tetramethyl-1,3-ethylenediamine. (Available from Aldrich.)

Foam Physical Properties

Splits indicates visible evidence and degree of splitting. This mayappear as a surface or interior foam split. A relative measure ofseverity may proceed this descriptor.

Cell Size indicates an actual measure of averaged cell size ranges usinga hand-held magnifying eyepiece with internal metric ruler.

% Settling indicates the percentage of foam height reduction at abornthe 4 minute post pour time relative to the maximum foam height duringthe first 3 minutes of foam rise.

Fingernailing is a subjective industry test which involves pressing thetingemails deeply into the foam sample and visually judging the speed atwhich the foam recovers. Fast recovery is desirable and is designated byadjectives such as good or mild fingernailing. Fingernailing should bemoderate to mild, though mild to non-existent is most preferred. Allother physical property testing of foam samples were performed accordingto ASTM D-3574 with minor modifications.

Lab Foam Production Methods

All of the all-water blown flexible foams were prepared using standard,box pour, hand mixture methods as described below. The polyol wasweighed into a half gallon paper mixing cup, followed by surfactant,amine(s), additive(s), and lastly the distilled water. This mixture wasthoroughly agitated for 60 or more seconds using a drill press basedblade mixing system (at 2500 RPM) which was attached to thepre-programmed timer. The drill press stopped for 15 seconds after theinitial mixing period (according to a pre-programmed schedule) in whichtime the pre-weighed amount of tin catalyst was added via syringe. Themixing then restarted and continued for 9 more seconds. At this time, apre-measured aliquot of TDI was added in one quick addition withcontinued stirring followed by additional mixing for 6 seconds. When thedrill press stopped, the liquid foam mass was poured as quickly aspossible into a cardboard box (14"×14"×6"). The blow off time wasmeasured as the time period from the initial TDI addition until gasrelease occurs. The gas release was recognized as bubbles appearingacross the surface of the foam. A sonar unit was used to measure foamheights for up to 5 minutes after initial mixing. The final foam riseand the percentage settle of the foam were recorded after the foam blowoff time. Compression sets and other physical properties were measuredaccording to ASTM 3574.

Comparative Examples A-H

The following two tables show the foam formulations and representativephysical properties of all-water based foams prepared using commerciallyavailable softening additives in low index, all-water-basedformulations. These are shown as Comparative Examples B-H versus a lowindex, all-water-based flexible foam without any additives (ComparativeExample A).

As these data show, foams using Additive A revealed very small IFDreductions versus Comparative Example A, the base case, while yieldinghigher 90% compression sets and fingernailing properties. Foams preparedwith Additive B showed significant IFD reductions, but also unacceptablecompression sets and tingemailing properties. Hence, these illustratethe problems present in the art before the present invention.

    ______________________________________    Formulations of Comparative Commercial Additive Foams                              Comparative    Chemical Components                    Example A Examples    of Foam Formulations                    Formulation                              B-H    ______________________________________    Polyol          100       100    Water (added)   5.25      5.25    TDI-80          64.38     64.84-66.67*    Index           85        85    Tin             0.1       0.1    Amine           0.18      0.18    Silicone        1.0       1.0    Modifier 1      5.0       5.0    Additive A      --        0.0-0.5    Additive B      --        0.0-0.5    ______________________________________     *depending on the reported hydroxyl numbers of the additives

    __________________________________________________________________________    Physical properties of Comparative Commercial Additive Foams                                            Air Flow,                                                 Degree of    Foam       Additive                    blow max. cell                              Density,                                  25% IFD                                       comp. sets                                            (AF) Finger-    Designation          Additive               amt. pphp                    time, sec                         size, mm                              pcf lb.  (%)  cfm/sf                                                 nailing    __________________________________________________________________________    A     none `    122  1.2  1.1 21.5 8.1  116  mild-moderate    B     A    0.1  126  1.4  1.1 21.0 36.2 140  moderate to server    C     A**  0.25 126  1.0  1.1 19.3 66.0 158  moderate    D     A    0.5  131  1.0  1.1 19.8 86.6 3    severe    E     B    0.1  124  1.5  1.1 18.5 40.0 126  moderate    F*    B    0.1  131  1.4  1.0 18.1 76.1 129  moderate to severe    G     B*** 0.25 131  1.4  1.1 15.0 88.3 4    severe    H     B    0.5  142  1.4  1.0 8.7  89.7 21   severe    __________________________________________________________________________     repeat of comparative example E. A + B do not fall within the scope of     invention     **9.4% settling     ***6.1% settling.     All other foams ≦ 2% settling.

Examples 1-11 and Comparative Examples A, I-R

The following two tables show the foam formulations and representativephysical properties of various flexible polyurethane foams preparedusing the amine softening additives and additive blends of the presentinvention. These foams are low index, all-water-based formulationsExamples 1-11 are made according to the present invention. ComparativeExamples A, I-R are shown for contrast to these examples. Example A isthe same as in the previous set of examples.

These foams show that additives C, D, E, G. and H alone or incombination with other additives yield lower IFD foams (versus the foamsof the present invention) with similar compression sets. The ComparativeExamples I-R typically show little or no softening in most cases usingcomparable levels of these amino additives of the present invention.When softening does occur with these comparative examples, as Example M,the compression sets are found to unacceptably high.

    ______________________________________    Formulations of Invention and    Comparative Commercial Additive Foams                             Examples 1-11 and    Chemical Components                   Comparative                             Comparative Examples    of Foam Formulations                   Example A 1-R    ______________________________________    Polyol         100       100    Water (added)  5.25      5.25    TDI-80         64.38     64.38    Index          85        85    Tin            0.1       0.1-0.13*    Amine          0.18      0.0-0.18*    Silicone       1.0       1.0    Modifier 1     5.0       5.0    Additive C     --        0.0-0.30    Additive D     --        0.0-0.25    Additive E     --        0.0--0.38    Additive F     --        0.0-0.5    Additives G-O  --        0.0-0.15    ______________________________________     *The catalyst levels of these formulations were slightly modified from     foam to foam to produce testable, splitfree foam with the individual     additives.

    __________________________________________________________________________    Physical Properties of Additive Foams                         max.         90%      Degree of    Foam       Add. amt.                    blow time,                         cell size,                              Dens.,                                  25% comp. sets                                           AF  Finger-    Designation          Additive               pphp sec  mm   pcf IFD lb.                                      (%)  cfm/sf                                               nailing                                                    Comments    __________________________________________________________________________    1     D    0.15 114  1.2  1.1 15.6                                      11.4 126 mild.                                                    improved hand    2     D    0.25 99   1.0  1.1 16.7                                      11.5 115 mild-                                                    improved hand                                               moderate    3     E    0.15 125  1.4  1.1 17.8                                      9.6  112 moderate-                                               severe-    4     E with               0.38 95   1.3  1.0 12.9                                      12.0 81  moderate                                                    improved hand          F    0.50    5     E with               0.15   121                         1.1  1.1 18.5                                      13.8 175 mild-          F    0.5                             moderate    6     E with               0.10 100  1.1  1.0 13.8                                      23.0 109 mild-          C    0.15                            moderate    7     D with               0.25 101  1.3  1.0 15.1                                      11.8 152 mild-          F    0.5                             moderate    8     C with               0.15 109  0.9  1.0 16.1                                      14.2 218 mild-          F    0.5                             moderate    9     C    0.3  93   1.2  1.0 14.4                                      12.9 179 mild-                                               moderate    10    G    0.15 110  1.5  1.1 18.5                                      14.3 121 moderate    11    H    0.15 95   2.1  1.0 19.4                                      13.0 89  mild-                                               moderate    Comparative    Examples    A     none --   1.22 1.2  1.1 21.5                                      81   116 mild-                                               moderate    I     F    0.5  128  1.2  1.0 21.7                                      15.0 149 mild-                                               moderate    J     B with               0.25 118  1.4  1.1 15.2                                      84   8   moderate-          F    0.5                             severe    K     A with               0.25 116  1.0  1.0 18.0                                      22   145 mild-          F    0.5                             moderate    L     I    0.15 84   2.0  1.0 22.5                                      29.5 87  moderate    M     J    0.15 116  2.0  1.0 17.8                                      42   108 moderate    N     K    0.15 95   2.0  1.0 21.5                                      27.8 115 moderate    O     L    0.15 113  1.8  1.1 21.0                                      14.8 167 mild-                                               moderate    P     M    0.15 92   2.0  1.0 18.5                                      73.3 69  moderate    Q     N    0.15 94   2.2  1.0 19.5                                      61.9 89  moderate    R     O    0.15 103  1.8  1.0 20.5                                      37.8 88  moderate    __________________________________________________________________________

Examples 12-13 and Comparative Example S

The following two tables show the foam formulations and representativephysical properties of various low index all-water blown foams preparedusing the softening amine additives and additive blends disclosed in thepresent invention. These are shown as Examples 12-13 versus a low index,all-water-based foam formulation. Comparative Example S, to highlightthe effect of foam density on foam properties.

These foams show that up to about 2.4 lb. of IFD reduction in highdensity foam, versus the high density Example S, was observed using theamino additives of the present invention.

    ______________________________________    Formulations of Higher Density Invention Additive Foams    Chemical Components                     Comparative                               Examples    of Foam Formulations                     Example S 12-13    ______________________________________    Polyol           100       100    Water (added)    2.65      2.65    TDI-80           39.68     39.68    Index            85        85    Tin              0.13      0.19    Amine            0.22      0.22    Silicone         1.3       1.3    Modifier 1       3.0       3.0    Additive D       --        0.0-0.15    Additive C       --        0.0-0.15    ______________________________________    Physical properties of High Density, Invention Additive Foams                                         90%   Air                     Additive blow  25%  comp. Flow,             Addi-   amt.     time, IFD  sets  (AF)             tive    pphp     sec   lb.  (%)   cfm/sf    ______________________________________    Comparative S             none    --       145   21.5 9.3   51.3    12       D       0.15     102   20.0 5.8   34.2    13       C       0.15     111   19.1 9.0   43.1    ______________________________________     All foams ≦3.0% settling.

Examples 14-16 and Comparative Example T

The following two tables show that the use of different modifiers withthe amine softening additives can result in even lower IFD values thanthe previous examples using Modifier 1. In these tables, Examples 14-16yielded IFD values or around 8-9 lbs. In comparison, Example 9 usingAdditive C and Modifier 1 yielded a 12.9 lbs. IFD value. Most otherphysical properties of these foams were similar.

    ______________________________________    Formulations Using Modifiers With Different Ratios    of Cell Openers to Crosslinking/Extending agent.                 Compar-                 ative    Chemical Components                 Example  Example  Example                                          Example    of Foam Formulation                 T        14       15     16    ______________________________________    Polyol       100      100      100    100    Water (added)                 5.1      5.1      5.25   5.25    TDI-80       65.9     65.9     65.1   65.1    Index        88       88       88     88    Tin          0.18     0.25     0.28   0.28    Silicone     1.3      1.3      1.3    1.3    Amine        0.35     0.25     0.25   0    Modifier 2   5.0      5.0      0      0    Modifier 3   0        0        5      5    Additive C   0        0.4      0.4    0.4    ______________________________________

    __________________________________________________________________________    Physical Properties of Invention Additive Foams                                     50%                 Additive                      Blow time,                            Density,                                25% IFD,                                     Comp. Sets                                          Airflow                                              Finger-           Additive                 amt., pphp                      sec.  pcf lbs  (%)  (cfm/sf)                                              nailing    __________________________________________________________________________    Comparative T           None  0    90    1.05                                22.3 15   65  mild    Example 14*           Additive C                 0.4  63    1.06                                8.7  6    114 very mild    Example 15           Additive C                 0.4  56    1.04                                8.99 9    80  very mild    Example 16           Additive C                 0.4  64    1.03                                9.62 7    95  very mild    __________________________________________________________________________     *very minor splits observed

We claim:
 1. A flexible slabstock polyurethane foam having a density ofless than 1.5 pcf comprising .Iadd.the reaction product of mixingtogether.Iaddend.:a. a polyol with substantially all secondary hydroxylfunctionality having an equivalent weight of about 400 to 1500grams/equivalent and an ethylene oxide content of less than 20%; b. anorganic isocyanate present at an index of 60-120; c. water at 1 to 12pphp; d. a surface active agent at 0.0001 to 5 weight percent; e. apolyurethane catalyst at 0.0001 to 5 weight percent; f. a foamprocessing aid at 0.2 to 10 pphp; and g. a tertiary amine polyisocyanatesoftening agent with at least one contiguous three carbon chain at 0.1to 2 pphp;wherein the foam has a 25% IFD of 5 to 18 pounds.
 2. A foamaccording to claim 1 wherein the tertiary amine polyisocyanate softeningagent is 1,3,5-tris-(3-dimethylaminopropyl)-1,3,5-triazine.
 3. A foamaccording to claim 1 wherein the tertiary amine polyisocyanate softeningis bis-(3-dimethylaminopropyl)methylamine.
 4. A foam according to claim1 additionally comprising ethylene oxide, propylene oxide based blockcopolymers which are terminated with a primary amine.
 5. A foamaccording to claim 1 wherein the foam processing is comprised of acrosslinking/extending agent and a cell opening agent.
 6. A foamaccording to claim 5, wherein the cell opening agent is a polyethyleneoxide adduct of glycerol of a molecular weight of about 990 gms/mole,with an equivalent weight of about
 330. 7. A process for making flexibleslabstock polyurethane foam having a density of less than 1.5 pcfcomprising mixing:a. a polyol with substantially all secondary hydroxylfunctionality having an equivalent weight of about 400 to 1500grams/equivalent and an ethylene oxide content of less than 20%; b. anorganic isocyanate present at an index of 60-120; c. water at 1 to 12pphp; d. a surface active agent at 0.0001 to 5 weight percent; e. apolyurethane catalyst at 0.0001 to 5 weight percent; f. a foamprocessing aid at 0.2 to 10 pphp; and g. a tertiary amino polyisocyanatesoftening agent with at least one contiguous three carbon chain at 0.1to 2 pphpsuch that the foam has a 25% IFD of 5 to 18 pounds.
 8. Aprocess according to claim 7 wherein the tertiary amine polyisocyanatecatalyst is 1,3,5-tris-(3-dimethylaminopropyl)-1,3,5-triazine.
 9. Aprocess according to claim 7 wherein the polyisocyanate catalyst isbis-(3dimethylaminopropyl)methylamine.
 10. A process according to claim7 additionally comprising ethylene oxide, propylene oxide based blockcopolymers which are terminated with a primary amine.
 11. A processaccording to claim 7 wherein the foam processing is comprised of acrosslinking/extending agent and a cell opening agent.
 12. A processaccording to claim 11, wherein the cell opening agent is a polyethyleneoxide adduct of glycerol of a molecular weight of about 990 gms/mole,with an equivalent weight of about
 330. 13. A polyurethane foamaccording to claim 1 wherein the the tertiary amine polyisocyanatesoftening agent is dimethylcyclohexyl amine.
 14. A method according toclaim 7 wherein the the tertiary amine polyisocyanate softening agent isdimethylcyclohexyl amine.
 15. A flexible slabstock polyurethane foamhaving a density of less than 1.5 pcf comprising .Iadd.the reactionproduct of mixing together.Iaddend.:a. a polyol with substantially allsecondary hydroxyl functionality having an equivalent weight of about400 to 1500 grams/equivalent and an ethylene oxide content of less than20%; b. an organic isocyanate present at an index of 60-120; c. water at1 to 12 pphp; d. a surface active agent at 0.0001 to 5 weight percent;e. a polyurethane catalyst at 0.0001 to 5 weight percent; f. a foamprocessing aid at 0.2 to 10 pphp; and g. a tertiary amine polyisocyanatesoftening agent with at least one contiguous three carbon chain at 0.1to 2 pphp;wherein the foam has a 25% IFD of 10 to 21 pounds.
 16. A foamaccording to claim 15 wherein the tertiary amine polyisocyanatesoftening agent is 1,3,5-tris-(3-dimethylammopropyl)-1,3,5-triazine. 17.A foam according to claim 15 wherein the tertiary amine polyisocyanatesoftening agent is bis-(3-dimethylaminopropyl)methylamine.
 18. Apolyurethane foam according to claim 15 wherein the the tertiary aminepolyisocyanate softening agent is dimethylcyclohexyl amine.